1. Field of the Invention
The present invention relates to an apparatus, such as a bed, having a vertically adjustable deck that is selectably raised and lowered in a substantially vertical manner under operation of two leg frames pivotally and movably connected to rails supporting the deck.
2. Description of the Related Art
Typically, height and angle adjustable beds are used by medical institutions, such as hospitals, nursing homes and/or long or short term care facilities. The beds usually include a bed frame and an articulating mechanism for lowering the bed frame to a low position and raising the bed frame to a high position so that it may be used as a gurney or at any height in between. As a result, a patient can be transferred by merely sliding the patient from one gurney to another or a chair.
Examples of beds include:
United States published application having publication number 2009/0094747 to Bly, and assigned to Invacare Corporation, is titled Bed Lift Mechanism. This publication illustrates a bed with a leg assembly coupled to a support link assembly by a joint, the joint comprising a slot having at least two paths. A support link assembly defining a length that automatically varies as the support link assembly moves relative to the leg assembly.
United States patent number (hereafter “U.S. Pat. No.”) 7,334,277 to Johnson, and assigned to Raye's, Inc. is titled Low Profile Hospital Bed. This patent shows a low profile hospital bed with a mattress support frame and pivotably mounted wheel frames. Lift actuators connecting between the mattress support frame and the wheel frames move the wheel frames between a folded position and an unfolded position. When the wheel frames are in the folded position, the lift actuators are relatively horizontal and thus unable to provide enough vertical force to move the wheel frames. Accordingly, connecting between the actuators and the wheel frames are leverage members which rotate and urge the wheel frames away from mattress support frame during an initial, first stage of movement as the wheel frames partially unfold. After the first stage of movement, the leverage members function as simple mechanical links between the lift actuators and the wheel frames as the lift actuators continue to power the complete unfolding of the wheel frames.
U.S. Pat. No. 6,729,667 to Henderson et al., and assigned to Howard Wright Limited, is titled Stretcher Suspension Linkages. It illustrates a linkage that includes a stretcher receiving frame and a base frame. A pair of arms are pivotally fixed to bottom frame and slidingly connected to frame. A pneumatic suspension unit is located between the arms and a first link pivotally coupled between arms and frame. A cross member of the slide coupling is coupled to a sliding mount of a second link pivotally coupled to an arm pivotally connected to the frame and sliding coupled to the base frame.
U.S. Pat. No. 6,473,922 to Sommerfeld et al., and assigned to Sunrise Medical HHG, Inc., is titled Kinematic Motion of Articulated Bed. This patent shows an articulated bed with a main frame supported by a leg tube. An upper portion of the leg tube is longitudinally and pivotally displaceable relative to the main frame at an upper movable pivot point. A lower portion of a stabilizer is connected to a lower intermediate portion of the leg tube at a lower orbital pivot point. An upper portion of the stabilizer is pivotally connected relative to said main frame at an upper fixed pivot point. A wheel is pivotally attached to a lower portion of the leg tube at a pivot axis. The upper movable pivot point, the lower orbital pivot point, and the pivot axis do not coalign and the distance between the upper fixed pivot point and the upper movable pivot point are maximized when the main frame is in a raised position. The bed of this invention is illustrated schematically in FIG. 10 where it is seen that a pivot axis D, pivot point C and pivot point B do not coalign.
U.S. Pat. No. 5,432,966 to Berta et al. is titled Adjustable Ambulance Cot with Trolley Mechanism. It shows an adjustable roll-in ambulance cot having a cot frame having a leading end, a trailing end, and a pair of opposing side frame members. The cot is supported by leading and trailing pairs of collapsible legs having respective upper ends connected to the cot frame and lower ends including transport wheels thereon for transport of the cot. Mechanisms are also provided for adjusting the height of the cot frame relative to the transport wheels and for latching the cot frame into a plurality of predetermined positions for patient transfer and loading.
U.S. Pat. No. 4,718,355 to Houghton is titled Vertically Adjustable Patient Support Table. It illustrates a patient support platform with a compound leg structure which allows the platform to move to a squatted position giving easy access for a patient or to disposition of a patient thereon and, at the same time, the platform is adjustable to elevated positions so that a standing attendant may administer to the patient. Supporting feet are disposed in a fixed, predetermined pattern and provide pivot points to which the compound leg structures are pivoted. The compound leg structures effect raising and lowering of the platform without changing or disturbing the positions of the feet.
U.S. Pat. No. 2,675,285 to Terry et al. is titled Vertically Adjustable Therapy Treatment Table having Hinged End Sections. It shows a table with folding legs. The legs are connected to and actuated by sleeves slidaby mounted on a threaded rod extended longitudinally through a supporting frame and rotated by a crank.
None of these references show a bed with structures adapted to level the loading output of the actuators by having a connection lever defining a path that is offset from a support frame cross member, wherein the position of the actuator end relative the connection lever path is controlled by a control arm.
None of these references shown a bed with outwardly angled leg frames with their pivots slidable along the bed frame, with a set of supports having a fixed longitudinal position extending from the bed frame to a central pivot point of the leg frames, and actuators are connected to the bed frame and to a movable pivotal connection point offset from the cross member.
None of these references show a bed with movably and pivotably connected legs, wherein the movable and pivotable connection is between the legs and a frame having a slotted bottom member (or tube) to provide symmetry at the connection, maintain structural integrity of the member and eliminate pinch points.
Thus there exists a need for an apparatus such as a bed that solves these and other problems.